Modern vehicle engineering has invested much time and effort, in recent years, towards solving the finer aspects of vehicle stability and traction control. Beginning with antilock brake control systems, newer controls including traction control, yaw moment control, and other forms of stability control have been developed and integrated into the braking control system to enhance overall vehicle stability and traction. At the same time, there has been a strong appearance of other controlled systems such as active suspension, active driveline control, active steering, etc. that are now being arranged on vehicles to enhance vehicle performance, maneuverability and secure driving impression. Many of these newer systems have capabilities to influence wheel slip, vehicle yaw, roll and pitch motions and have specific strategies of control. However, many of these systems may have differing strategies to control various vehicle response parameters and conditions and lend themselves to interference. That is to say that these various actuator systems (i.e., brake systems, throttle control systems, chassis damping systems, etc.) have been designed and implemented to work independently of one another despite being arranged on the same vehicle.
In the present state of the art, various control systems applied on the same vehicle generally operate with separate functionality and do not share more than minimal information to understand the status of other systems' functioning capability. In some cases actions of two control systems attempting to perform similar function or working in a similar domain of operation (such as controlling wheel slip, vehicle yaw rate, etc.) can have interference. As an example of this type of interference, consider a vehicle which is fitted with an electronic driveline system capable of generating wheel torques independently at each wheel and a brake-based stability control system also capable of generating wheel torques independently at each wheel. In various operational regimes, the electronic driveline system may be requesting various wheel torques in either a feed-forward and/or feedback manner, and simultaneously the brake-based control system is working to reduce wheel slip and/or excessive vehicle yawing motions. Depending on how the systems are calibrated it is possible to have interference wherein the driveline system attempts to increase wheel torque on a given wheel, while the brake system attempts to reduce the wheel torque. This situation occurs because each control system has different targets for wheel slip and/or yaw control using reference signals for the control that may not be calculated in the same manner, hence interference occurs.
What is desired is a system and method to control undesirable vehicle phenomena such as wheel slippage, wheel lockup and vehicle spinouts in harmony between various control and actuator systems. What is desired is a system and method where these systems, each benefit from the information and control of other subsystems in the vehicle. Further, if one system malfunctions, other systems should be able to compensate in some way.